Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, ul. Kosygina 4, 119334 Moscow, Russian Federation.
Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, ul. Kosygina 4, 119334 Moscow, Russian Federation; Moscow Institute of Physics and Technology (National Research University), Institutskii per. 9, 141701 Dolgoprudny, Moscow Region, Russian Federation.
Spectrochim Acta A Mol Biomol Spectrosc. 2024 Dec 15;323:124941. doi: 10.1016/j.saa.2024.124941. Epub 2024 Aug 6.
A study on the absorption and fluorescence properties of the 8-anilino-1-naphthalenesulfonate (ANS) fluorescent probe was performed in order to (i) verify the validity of its classification as hydrophobic probe and (ii) to assess the reliability of the interpretation of the ANS fluorescence enhancement upon protein binding as the evidence for the existence of hydrophobic binding sites on the protein molecules. We observed an enhancement of the ANS fluorescence in hydrophilic media: DMSO, polyethylene glycol (PEG400) and glycerol to the values characteristic of ANS complexes with globular proteins, and all ANS fluorescence characteristics (except anisotropy) in PEG400 and in complex with bovine serum albumin are identical. We observed an increase in the ANS fluorescence with a nonzero anisotropy in an aqueous medium in the presence of an amphiphilic cetyltrimethylammonium cation as a result of the formation of the 1:1 complex with ANS. Water molecules quench the fluorescence of ANS. The enhancement of the ANS fluorescence in aqueous media in the presence of fluorescence enhancers is accounted for by their blocking the access of water molecules to the region close to the excited ANS molecule, which is critical for the fluorescence.
研究了 8-苯胺-1-萘磺酸盐（ANS）荧光探针的吸收和荧光性质，目的是：(i)验证其被归类为疏水探针的有效性；(ii)评估蛋白质结合后 ANS 荧光增强的解释的可靠性，作为蛋白质分子上存在疏水结合位点的证据。我们观察到在亲水介质（DMSO、聚乙二醇（PEG400）和甘油）中 ANS 荧光增强，其值与球状蛋白质与 ANS 的复合物特征值一致，PEG400 中的所有 ANS 荧光特性（各向异性除外）和与牛血清白蛋白的复合物相同。我们观察到在含有两亲性十六烷基三甲基铵阳离子的水介质中，由于形成 1:1 与 ANS 的复合物，ANS 的荧光伴随着非零各向异性增加。水分子会猝灭 ANS 的荧光。在荧光增强剂存在下，水介质中 ANS 荧光增强归因于它们阻止水分子进入靠近激发态 ANS 分子的区域，这对荧光至关重要。
